Electromagnets



H. J. TYLER ELECTROMAGNETS June 28, 1960 2 Sheets-Sheet 1 Filed July 11, 1957 H. J- TYLER ELECTROMAGNETS June 28, 1960 2 Sheets-Sheet 2 Filed July 11, 1957 INVENTOR. fl zhlzyler. BY

ATY'OM United States Patent ELECTROMAGNETS Hugh J. Tyler, Jeannette, Pa., assignor to Robertshaw- Fulton Controls Company, Richmond, Va., a corporation of Delaware Filed July 11, 1957, Ser. No. 671,161

6 Claims. (Cl. 317-165) This invention relates to electromagnets and more particularly to improvements in the winding therefor. V

Electromagnets having a horseshoe or U-shaped magnet element have embodied a winding of insulated wire on each leg of the magnet. The magnet has been secured to a support by riveting or bolting through the base portion between the legs. Such construction tends to make the magnet legs unnecessarily long to accommodate the required winding. The magnet may also become distorted during the securing process, thus destroying the uniformly flat surface necessary on the pole faces which the armature must engage. Moreover, in cases where the electromagnet is subjected to high ambient temperatures, the insulating winding may have a relatively short life.

An object of this invention is to reduce the size of an electromagnet while retaining desired operating characteristics.

Another object of the invention is to clamp the magnet element securely in position without tending to distort it.

Another object of the invention is to cushion the magnet element in supported position.

Another object of the invention is to eliminate materials which may be subject to destruction under high ambient temperatures.

Another object of the invention is to reduce the cost of manufacturing by simplifying the assembly and using less expensive parts.

An electromagnet incorporating these and other objects and advantages may comprise the usual horseshoe magnet element having relatively short legs connected by a base. A fiat strip of metallic conducting material is wound in a plurality of turns around the base and the opposite ends are folded outwardly as terminal tabs. A U-shaped clamp extends over the turns and the magnet base and is secured in the support. The assembly is completed by connecting lead wires to the tabs and fastening the assembly in the usual magnet housing.

In the drawings:

Fig. l is an elevation, partly in section, of the improved electromagnet;

Fig. 2 is a top plan View;

Fig. 3 is a partial section taken on the line III-III of Fig. 2; and

Fig. 4 is an exploded perspective view of the assembly.

Referring more particularly to the drawings, the electromagnet comprises a housing of cup-shaped form and which may conveniently be made of sheet metal by drawing and cupping operations. The bottom of the housing 10 is perforated and the wall of the opening so formed is turned inwardly, as at 12. The inturned wall 12 forms a supporting surface for the usual armature 14 which is a circular disc having a stem 16 projecting through the aperture and guided by the inturned wall 12. A coil spring 18 encircles the projecting end of the stem 16 and has one end abutting a spring retainer 26 secured on the stem 16 by a U-shaped retaining washer 22. The opposite end of the coil spring 18 is internally supported on the outer wall of a hollow guide element 24 which may also be Patented June 28, 1960 ice formed of sheet material and secured to the housing 10 overlying the aperture in the inturned wall 12. Since the parts just described form no part of this invention and may be reconstructed as desired, further description is deemed unnecessary.

The opposite open end of the housing 10 is provided with an annular recess 26 for thereception of a support plate 28 which may be secured in position by spinning or otherwise forming the end of the housing 10 thereover. The support plate 28 is provided with an annular depression 30 leaving a central support portion 32 on the inner wall of the plate 28.

This invention is more particularly directed toward the provision of an improved magnet element and winding therefor, both of which are supported in the housing 10 and occupy a minimum of space. The housing 10 may accordingly be considerably shorter in length than comparable structures as will be apparent as this description proceeds. To this end, a magnet element 34 of the usual horseshoe or U-shaped form is provided. However, in this instance, the oppositely disposed legs 36, 36 of the magnet element 34 are relatively short and are connected by a base portion 38. The relative shortness of the legs 36, 36 is possible due to the absence of any winding thereon.

In this embodiment, a winding 40 of conducting material is provided for the magnet element 34 and takes the form of a flat metal strip wound in a plurality of turns or laminations around the base 38 and spaced from the legs 36, 36. A suitable metallic material is aluminum foil and this may be coated with natural oxide for high temperature insulation. The winding 40 has its inner end 42 and its outer end 44 folded perpendicularly outward and projecting in opposite directions from the turns of the winding 40. The ends 42, 44 thus form terminal tabs to which a pair of conductors or lead wires 46, 48, respectively, are connected.

The magnet element 34, together with the winding 40, is secured in the housing 10 by a U-shaped clamp 50. The clamp 50 has its median portion positioned between the legs 36, 36 of the magnet element 34 and overlying the turns of the winding 40. The oppositely disposed arms of the U-shaped clamp 50 extend over opposite ends of the winding 40 into contact with the support plate 28. An interlocking arrangement for clamping the magnet element 34 and the winding 40 together and to the support plate 28 is provided. In this embodiment, a pair of slots 52 is formed in the support plate 28 outwardly of the depression 30 therein for the reception of the oppositely disposed arms of the clamp 50 which may be crimped or otherwise formed as at 54 to secure the clamp 50 in position. The turns of the winding 40 between the base 38 of the magnet element 34 and the support plate 28 are seated upon the support portion 32.

The lead wires 46, 48 extend exteriorly of the housing 10 and the support plate 28 is suitably apertured for this purpose. As is apparent, the lead wires may be connected to a source of electric energy which is conducted to the winding 40. The resulting magnetic flux will attract the armature 14 toward the pole faces formed on the ends of the legs 36, 36 of the magnet element 34. Upon de-energization of the winding 40, the armature 14 will return to its supported position on the inturned wall 12 under bias of the coil spring 18.

The winding 40 comprising the plurality of laminations or turns around the base 38 of the magnet element 34 forms a cushion for the magnet element 34 during a sembly and in use. Thus, there is no tendency to deformation of the magnet element 34 during assembly in the housing 10 by the clamp 50. Considerable magnet material is saved by utilizing the base 38 of the magnet element 34 for the winding 40 instead of legs 36, 36, and more efiicient use is made of the window area of the magnet invention as defined in the appended claims.

I claim: 1. In an electromagnet having an armature, a magnet element having a pair of legs connected by a base and defining a pair of pole faces respectively for the armature, a winding of conducting material for said magnet, said material being in the form of a flat strip and wound in a plurality of turns around said base, a support member, means extending around in engagement with said Winding and secured to said support member for clamping said magnet element and winding together and to said support member, and a pair of conductors carried by opposite ends of said winding respectively.

2. In an electromagnet having an armature, a magnet element having a pair of legs connected by a base and defining a pair of pole faces respectively for the armature, a winding of conducting material for said magnet, said material being in the form of a flat strip wound in a plurality of turns around said base and spaced from said legs, said winding having opposite ends projecting therefrom to form terminal tabs thereon, a support member, means extending around in engagement with said winding and secured to said support member for clamping said magnet element and winding together and to said support member, and a pair of lead wires connected to said terminal tabs respectively.

3. In an electromagnet having an armature, a magnet element having a pair of legs connected by a base and defining a pair of pole faces respectively for the armature, a winding of conducting material for said magnet, said material being in the form of a flat strip wound in a plurality of turns around said base, a support plate engaging one side of said winding, a clamp having aportion engaging the opposite side of said winding and a pair of oppositely disposed arms extending to said plate, said arms and plate having interlocking engagement for clamp ing said magnet element and winding together and to said plate, and a pair of conductors carried by opposite end of said winding respectively.

4. In an electromagnet having an armature, a magnet element having a pair of legs connected by a base and defining a pair of pole faces respectively for the armature, a winding of metallic conducting material for said magnet, said material being in the form of a fiat strip wound in a plurality of turns around said base and spaced from said legs, said winding having opposite ends folded perpendicularly outward and projecting from said turns to form terminal tabs, a support plate engaging one side of said winding adjacent one of said tabs, a clamp having a median portion engaging the opposite side of said winding adjacent the other said tab, said clamp having a pair of oppositely disposed arms extending over opposite ends of said Winding normal to said legs and into contact with said plate, said arms and plate having interlocking engagement for clamping said magnet element and winding together and to said plate, and a pair of lead wires connected to said terminal tabs respectively.

5. An electromagnet as claimed in claim 4 wherein said conducting material is aluminum foil. 1

6. An electromagnet as claimed in claim 5 wherein said aluminum foil is oxidized for high temperature insulation.

References Cited in the file of this patent UNITED STATES PATENTS 2,406,265 Syrovy Dec. 20, 1946 2,521,513 Gray Sept. 5, 1950 2,710,947 Gaston June 14, 1955 2,722,891 Weinfurt NOV. 8, 1955 FOREIGN PATENTS 439,901 Great Britain Dec. 17, 1935 

